Mammograms Cut Risk of Breast Cancer Death

Oct. 6, 2009 -- Three-fourths of deaths due to breast cancer occur among women who do not undergo regular screening mammograms, a large study shows.

Researchers studied 6,997 women who were diagnosed with breast cancer in Massachusetts between 1990 and 1999. Surveys indicated that 80% had regular mammograms, defined as at least two screening mammograms every two years.

Over the next 13 years, there were 461 deaths from breast cancer; 345 (75%) were among women who did not receive regular mammograms and 116 (25%) were among women who were regularly screened.

The researchers then extrapolated the results to the more than 192,000 women who will be diagnosed with invasive breast cancer in the U.S. in 2009. It’s estimated that, overall, 15% of these women will die over the next 13 years, says study head Blake Cady, MD, emeritus professor of surgery at Harvard Medical School.

But when looked at by their mammogram history, only 5% of those who were regularly screened are expected to die by 2022, he says.

In contrast, 56% of those who skipped regular mammograms are expected to die over the same period -- a rate similar to 1970, before the widespread use of mammography, Cady tells WebMD.

The findings were released at a news conference with the American Society of Clinical Oncology in advance of the 2009 Breast Cancer Symposium in San Francisco.

Benefits of Mammography

Other studies have shown that regular mammograms, which help detect breast cancers at earlier, more curable stages, cut the risk of dying from breastcancer by anywhere from 25% to over 50%.

But Cady says the large, population-wide analysis helps to better illustrate the practical benefits of mammography. The hope is that the “powerful figures” will convince more women to have regular mammograms -- ideally every year starting at age 40, he says.

There are a number of barriers to more widespread screening, such as lack of insurance, Cady acknowledges.

Still, “this is something many women can easily do to reduce their chance of dying from breast cancer,” he says.

Some women, for example, shy away from screening because they’re scared of false-positives leading to unnecessary biopsies and anxiety, Cady notes. His response: “When you look at the huge reduction in deaths that can be avoided by mammography, concerns about false-positives and having to undergo biopsies seem minor.”

The findings “remind us that mammography is one of the most powerful tools we have for improving breast cancer survival rates,” says Lori Pierce, MD, professor of radiation oncology at the University of Michigan School of Medicine, who moderated the news conference.